First day at the Geology Department. The three types of stones in the rock cycle are the igneous stone, sedimentary stone and the metamorphic stone.

The igneous rock happens because liquid magma hardens either above (extrusive rock) or under (intrusive rock) Earth’s surface. Obsidian is simply beautiful by the way!

Sedimentary rock is formed when layers of the sediments from the igneous rock as well as sand from the sea bed is packed under high pressure and temperature. It is compacted in a rock. It is lighter because it has more air spaces compared to the igneous rock, which is heavy and dense.Conglomerates, that’s the one Curiosity discovered on its journey to Mt. Sharp – more evidence to channels of water on Mars. The ones on Mars are essentially a bunch of gravel fused together…and since MOST of the gravel is rounded, that could only mean it’s worn out by water (their too heavy to be transported by wind),like the pebbles we find in rivers.

The metamorphic rock is formed when igneous rocks and sedimentary rocks are submerged underground (where rocks originated from in the fist place as magma) under high pressure and temperature, but it doesn’t melt. I swear we saw a migmatite, a rock at its last stage of metamorphism where it’s so close to melting (it escapes the melt though), though the department labelled it a gneiss. A feature of these metamorphic rocks is “foliation”: the alignment of crystals in the rock in a direction perpendicular to the stress/compressive force applied onto it.